Support legacy devices

Simulate MT touch events for legacy devices that support the
DOUBLETAP, TRIPLETAP and QUADTAP events. This allows multi-finger
tap and drag gestures to be emitted, providing a basic level of
MT functionality for legacy devices.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

2 files changed, 122 insertions, 2 deletions

diff --git a/src/touch-caps.c b/src/touch-caps.c
index 7f243c5..a51912c 100644
--- a/src/touch-caps.c
+++ b/src/touch-caps.c
@@ -21,6 +21,7 @@
  ****************************************************************************/
 
 #include <grail-touch.h>
+#include <errno.h>
 #include <math.h>
 
 /* see mtdev-mapping.h */
@@ -29,6 +30,42 @@
 #define MTDEV_ORIENTATION       4
 #define MTDEV_PRESSURE          10
 
+#define SYSCALL(call) while (((call) == -1) && (errno == EINTR))
+
+static const int bits_per_long = 8 * sizeof(long);
+
+static inline int nlongs(int nbit)
+{
+        return (nbit + bits_per_long - 1) / bits_per_long;
+}
+
+static inline int getbit(const unsigned long *map, int key)
+{
+        return (map[key / bits_per_long] >> (key % bits_per_long)) & 0x01;
+}
+
+int touch_caps_is_supported(struct touch_dev *dev, int fd)
+{
+        unsigned long keybits[nlongs(KEY_MAX)];
+        unsigned long absbits[nlongs(ABS_MAX)];
+        int rc;
+
+        if (dev->mtdev.caps.has_mtdata)
+                return 1;
+
+        SYSCALL(rc = ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybits)), keybits));
+        if (rc < 0)
+                return 0;
+        SYSCALL(rc = ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbits)), absbits));
+        if (rc < 0)
+                return 0;
+
+        return getbit(absbits, ABS_X) &&
+                getbit(absbits, ABS_Y) &&
+                getbit(keybits, BTN_TOUCH) &&
+                getbit(keybits, BTN_TOOL_DOUBLETAP);
+}
+
 void touch_caps_init(struct touch_dev *dev)
 {
         const struct mtdev_caps *mt = &dev->mtdev.caps;
diff --git a/src/touch-dev.c b/src/touch-dev.c
index 17082ed..d8e192e 100644
--- a/src/touch-dev.c
+++ b/src/touch-dev.c
@@ -53,13 +53,45 @@ static void finish_touch(struct touch_dev *dev, struct touch_frame *frame)
         dev->state = 0;
 }
 
+static void finish_legacy(struct touch_dev *dev, struct touch_frame *frame)
+{
+        static int trkid;
+        int i;
+        for (i = 0; i < frame->nactive; i++) {
+                struct touch *t = &frame->touch[i];
+                t->active = 1;
+                if (t->id < 0) {
+                        t->id = trkid++ & 0xffff;
+                        frame->ncreate++;
+                }
+                if (i > 0) {
+                        SET_PROP(x, frame->touch[0].x);
+                        SET_PROP(y, frame->touch[0].y);
+                        SET_PROP(pressure, frame->touch[0].pressure);
+                }
+                grail_mask_set(frame->touches, i);
+        }
+        for (i = frame->nactive; i < DIM_TOUCH; i++) {
+                struct touch *t = &frame->touch[i];
+                t->active = 0;
+                if (t->id >= 0) {
+                        t->id = -1;
+                        frame->ndestroy++;
+                }
+                grail_mask_clear(frame->touches, i);
+        }
+}
+
 static void finish_packet(struct touch_dev *dev,
                           const struct input_event *syn)
 {
         static const touch_time_t ms = 1000;
         struct touch_frame *frame = &dev->frame;
         int i, nslot = 0;
-        finish_touch(dev, frame);
+        if (dev->mtdev.caps.has_mtdata)
+                finish_touch(dev, frame);
+        else
+                finish_legacy(dev, frame);
         grail_mask_foreach(i, frame->touches, DIM_TOUCH_BYTES)
                 frame->active[nslot++] = &frame->touch[i];
         frame->nactive = nslot;
@@ -77,6 +109,21 @@ static int handle_abs_event(struct touch_dev *dev,
         struct touch_frame *frame = &dev->frame;
         struct touch *t = &frame->touch[dev->slot];
         switch (ev->code) {
+        case ABS_X:
+                if (dev->mtdev.caps.has_mtdata)
+                        return 0;
+                SET_PROP(x, ev->value);
+                return 0;
+        case ABS_Y:
+                if (dev->mtdev.caps.has_mtdata)
+                        return 0;
+                SET_PROP(y, ev->value);
+                return 0;
+        case ABS_PRESSURE:
+                if (dev->mtdev.caps.has_mtdata)
+                        return 0;
+                SET_PROP(pressure, ev->value);
+                return 0;
         case ABS_MT_SLOT:
                 if (ev->value >= 0 && ev->value < DIM_TOUCH) {
                         if (dev->slot != ev->value)
@@ -128,6 +175,40 @@ static int handle_abs_event(struct touch_dev *dev,
         }
 }
 
+static int handle_key_event(struct touch_dev *dev,
+                            const struct input_event *ev)
+{
+        struct touch_frame *frame = &dev->frame;
+        if (dev->mtdev.caps.has_mtdata)
+                return 0;
+        switch (ev->code) {
+        case BTN_TOUCH:
+                if (ev->value && !frame->nactive)
+                    frame->nactive = 1;
+                else if (!ev->value && frame->nactive)
+                    frame->nactive = 0;
+                return 0;
+        case BTN_TOOL_FINGER:
+                if (ev->value)
+                        frame->nactive = 1;
+                return 0;
+        case BTN_TOOL_DOUBLETAP:
+                if (ev->value)
+                        frame->nactive = 2;
+                return 0;
+        case BTN_TOOL_TRIPLETAP:
+                if (ev->value)
+                        frame->nactive = 3;
+                return 0;
+        case BTN_TOOL_QUADTAP:
+                if (ev->value)
+                        frame->nactive = 4;
+                return 0;
+        default:
+                return 0;
+        }
+}
+
 int touch_dev_open(struct touch_dev *dev, int fd)
 {
         struct touch_frame *frame = &dev->frame;
@@ -139,7 +220,7 @@ int touch_dev_open(struct touch_dev *dev, int fd)
                 t->id = MT_ID_NULL;
         }
         ret = mtdev_open(&dev->mtdev, fd);
-        if (!ret && !dev->mtdev.caps.has_mtdata)
+        if (!ret && !touch_caps_is_supported(dev, fd))
                 ret = -ENODEV;
         if (ret)
                 goto error;
@@ -166,6 +247,8 @@ int touch_dev_pull(struct touch_dev *dev, int fd)
                         consumed++;
                 } else if (ev.type == EV_ABS) {
                         consumed += handle_abs_event(dev, &ev);
+                } else if (ev.type == EV_KEY) {
+                        consumed += handle_key_event(dev, &ev);
                 }
                 if (!consumed && dev->event)
                         dev->event(dev, &ev);